1. Field of the Invention
The present invention relates to a display system in which a flat display de vice and a driving part therefore can be detachably attached to each other.
2. Description of the Related Art
For example, a liquid crystal display is well known as a flat display system. In the case of the liquid crystal display, it is general to directly connect its driving circuit to its display substrate by using TAB mounting or flip chip mounting. In this method, a driving device including one set of driving circuits is needed for one set of displays. For this reason, there is the problem that the liquid crystal device becomes an expensive device having a large area, a heavy weight and a large thickness. Because of this problem, it has been impossible to apply the method to, for example, an application which uses a plurality of displays.
As an art which solves the above-described problem, there is a display system in which its display device part and its driving device part are separated from each other and a plurality of display devices having no driving devices are driven by one set of driving devices. FIG. 17 is an explanatory view showing one example of a conventional display system. In FIG. 17, reference numeral 71 denotes a display device, reference numeral 72 denotes driving devices and reference numeral 73 denotes a binding part. This display system includes the plurality of display devices 71 and one driving device 72 having the binding part 73. The display devices 71 are connected together in a book-like form by the binding part 73.
In the above-described construction, since the display devices 71 are not integrated with the driving device 72, each of the display devices 71 can be formed as a thin and light-weight display device and is easy to handle. For this reason, it is possible to construct the display system using the plurality of display devices 71 as shown in FIG. 17.
FIG. 18 is a perspective view showing one example of electrical connection means for the display device 72 and the driving devices 71 in one example of the conventional display system. In FIG. 18, reference numeral 74 denotes electrode terminals, and reference numeral 75 denotes a card edge connector. A system disclosed in, for example, Japanese Patent Laid-Open No. 254420/1990, which uses the card edge connector 75 of the type shown in FIG. 18, is known as means for electrically connecting the display devices 71 and the driving device 72 in the display system shown in FIG. 17.
In this system, the electrode terminals 74 are provided at an end portion of each of the display devices 71, and the end portion at which the electrode terminals 74 are provided is inserted into the card edge connector 75. Electrodes which respectively correspond to the electrode terminals 74 of each of the display devices 71 are disposed in the card edge connector 75, and when one display device 71 is inserted into the card edge connector 75, the electrodes of both the card edge connector 75 and the display device 71 slide into contact with each other to provide electrical connection.
However, this electrical connection system which uses the card edge connector 75 has the disadvantage that because a large area in which to dispose the electrode terminals 74 is needed around the image display area of the display devices 71, the area of the display devices 71 is large. Even in a display system such as that shown in FIG. 17, the binding part 73 needs a construction which corresponds to the card edge connector 75, so that the area of the driving device 72 is large and the entire display system is large.
Furthermore, since the display devices 71 are attached and detached by a multiplicity of times, the electrode terminals 74 repeatedly slide on the electrode terminals in the card edge connector 75. For this reason, the electrode terminals 74 of the display devices 71 need the reliability of electrical connection and wear resistance. Therefore, the electrode terminals 74 must be covered with Au plating having an intermediate metallic layer. However, there is the problem that it is difficult in terms of techniques and costs to apply Au plating or the like to an ITO layer or an Al layer which is generally used for display board lines.